DESMATOCHELYID. 185 
This genus is a most interesting one, inasmuch as it shows evident relationships with the 
Cheloniidz, and at the same time presents characters which must be regarded as more primitive 
than those of the latter family. Among these characters is the possession of well-developt 
nasal bones. ‘The choanz too have their primitive position just behind the premaxilla and are 
separated by the body of the vomer. In the Cheloniide the latter bone sends downward a 
perpendicular plate, the lower border of which expands laterally and joins horizontal plates 
of the maxilla and of the palatines, forming a floor beneath the narial passages and pushing 
the choane further backward. The possession of small posterior palatine foramina shows a 
closer connection with Amphichelydian stock than exists in the Cheloniida, which have lost 
these foramina. 
Williston thinks that the cervical vertebra indicate pleurodiran characters. The posses- 
sion of strongly developt transverse processes is to be regarded as an inheritance rather from 
the Amphichelydia than from the Pleurodira. The articular ends of the cervical vertebre 
show decided affinities with the Cryptodira. An intervertebral articulation which is 26 mm. 
wide and only 15 mm. high, belonging to a centrum only 26 mm. long, would not lend itself 
readily to flexure sidewise, while it would permit easy flexure in a perpendicular plane. 
The Desmatochelyidz are to be arranged close to the Cheloniida; but their many prim- 
itive characters demand that they be kept in a distinct family. For those who are seeking a 
Cretaceous ancestor for the modern sea-turtles, Desmatochelys presents itself as a more eligible 
form than any of the Cretaceous Thalassemydide. 
Fics. 238 AND 239.—Desmatochelys lowt. Skull of type. 4. 
238. Upper surface. 239. Seen from below. 
Desmatochelys lowi Williston. 
Figs. 238-243. 
Desmatochelys lowii, Witiiston, Kansas Univ. Quart., m1, 1894, p. 5; Univ. of Kansas Geol. Sury. 
Iv, 1898, p. 353, plates Ixxiii-Ixxvili—Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 443- 
The original and only known materials belonging to the present species are the property 
of the University of Kansas. They consist of the skull, finely preserved, but lacking the hinder 
part of the base; 3 cervical, the sacral, and some caudal vertebre; the pectoral girdle, the 
humerus, radius, and some metacarpal bones; most of the pelvic bones and an incomplete 
femur; some fragments of the carapace and some of the plastron. The animal was appa rently 
preserved in fine condition, but was damaged in collecting. The remains were found in Benton 
